Busbars shrouds

In the cubicle construction of a switchgear assembly the busbar chamber is normally located at the top of the assembly and runs through the length of it. It is usually suitable for extension, through fish joints at either end, if required at a later date. For installations having top cable entry, the busbar chamber may also be located at the bottom of the assembly or the depth of the panel increased, with an additional shroud between the top busbar chamber and cable chamber. From these main busbars are tapped the vertical buses for each vertical panel. Manufacturers may adopt different practices for horizontal and vertical busbar arrangements to economize on their cost of production. We illustrate the most common types of busbar arrangements. 

A separate control wireway may also run through the same busbar chamber, with suitable segregation or shrouding between the main bus and the control bus. This arrangement can be seen in Figures 13.2 and 13.7. The control bus system may be required for one or more auxiliary supplies for the following auxiliary services. 

For safety reasons, the busbar chamber and the cable alley should be separate and shrouded from each other. 

Faults can occur within the busbar and riser compartments of switchboards. However, modern switchgear is very reliable and snch fanlts are rare. Many pnrchasers of switchgear specify insulated and segregated bnsbars and risers, with all the connectors, clamps, nnts and bolts to be fully shrouded with flame retardant material, see sub-section 7.2.4. 

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